1. Field of the Invention
The present invention relates to an endoscope including an insertion portion to be inserted into a subject and an operation portion connected in series to a proximal end in an insertion direction of the insertion portion to be grasped and operated by an operator.
2. Description of the Related Art
In recent years, an endoscope has been widely used in a medical field and an industrial field. With an endoscope for use in the medical field, it is possible to observe an organ inside a body cavity as a subject by inserting an elongated insertion portion into the body cavity, and as necessary perform various kinds of treatment using a treatment instrument that is inserted into a treatment instrument insertion channel provided in the endoscope.
Further, with an endoscope for use in the industrial field, by inserting an elongated insertion portion of the endoscope into an object such as a jet engine or pipes in a factory, it is possible to perform an examination such as an observation of flaws or corrosion or the like at a site to be examined inside the object, and various kinds of treatment.
Further, an image pickup unit for picking up an image inside the subject or object is provided in a distal end portion which is located on a proximal end side in an insertion direction of the insertion portion of the endoscope (hereinafter referred to simply as “proximal end side”). An image of a site of the subject or object which is picked up by the image pickup unit is converted into an electric signal (hereinafter referred to as “image pickup signal”) by the image pickup unit. Thereafter, the image pickup signal is transmitted through a signal cable having one end connected to the image pickup unit inside the insertion portion of the endoscope, an operation portion connected in series to a proximal end in the insertion direction of the insertion portion (hereinafter simply referred to as “proximal end”), a universal cord extended from the operation portion and a connector provided at an extended end of the universal cord, and further transmitted to an external apparatus by the connector being connected to the external apparatus and is displayed on a monitor provided at the external apparatus.
Furthermore, in the operation portion, a bending drive mechanism for bending a bending portion provided at a proximal end of the distal end portion on a distal end side of the insertion portion, a light guide for transmitting illumination light to a distal end in the insertion direction of the insertion portion (hereinafter simply referred to as “distal end”), and various types of tubes for supplying a liquid and an air to the distal end of the insertion portion.
Here, in Japanese Patent Laid-Open Publication No. 2009-005836, there is disclosed a configuration in which a motor used in electrically driving the bending drive mechanism and electric parts such as a substrate for controlling drive of the motor are provided in the operation portion.
Besides, as the electric part provided in the operation portion, an electric substrate is provided for preventing the image pickup signal from being attenuated while the image pickup signal transmits from the image pickup unit to the external apparatus because the signal cable is too long. In other words, in order to obtain an image of higher quality there are provided an electric substrate that is electrically connected to the signal cable at an intermediate position in the operation portion and amplifies the image pickup signal, and an electric substrate for driving and controlling a light source in a case where the light source is provided in the operation portion.